This paper discusses research carried-out on the development and validation (on a real plant)
of a parity-equation and Kalman filter based fault detection and isolation (FDI) system for a pneumatic
actuator. The parity and Kalman filter equations are formulated and used to generate residuals that, in
turn, are analysed to determine whether faults are present in the system. Details of the design process are
given and the experimental results are compared. The results demonstrate that both approaches can
successfully detect and isolate faults associated with the sensors, actuators (servo-valves and piping) and
the pneumatic cylinder itself. The work is part of a BAE SYSTEMS sponsored project to demonstrate
advanced control and diagnosis concepts on an industrial application.